Stabilized salad oils



United States Patent O 3,211,558 STABILIZED SALAD OILS Fredric J. Baur,Cincinnati, Ohio, assignor to The Procter & Gamble Company, Cincinnati,Ohio, a corporation of Ohio No Drawing. Filed Aug. 9, 1962, Ser. No.215,790 9 Claims. (Cl. 99-118) This invention relates to improved saladoils. More particuarly, it relates to oils which can be stored atrelatively low temperatures for extended periods of time withoutclouding, and which are capable of being used in preparing mayonnaiseemulsions which themselves can be stored at low temperatures.

Oils which are suitable for salad use are frequently stored inrefrigerators. The prolonged cooling of such oils to temperaturesnormally encountered in refrigerators, such as from about 40 to about 50F., generally results in the deposition of crystalline material, usuallysolid triglycerides, from the oil. This material may appear in the formof a cloud, or as a group of crystals, and is considered objectionableby the housewife. The tendency to form solid glycerides in oils alsoadversely affects the suitability of the oil for use in mayonnaiseemulsions. Mayonnaise emulsions prepared from such oils tend to beunstable at low temperatures and are more easily broken.

Frequently it is desirable to hydrogenate natural Vege table oils, suchas soybean oil, in order to improve their oxidative stability. Thishydrogenation will tend to raise the melting point and to producecomponents of decreased solubility in the oils, causing them to have theundesirable properties listed hereinbefore.

A large proportion of the high melting glycerides can be removed fromoils by the process known as winterizing in which the oils are carefullycooled to low temperatures for extended periods of time to permitprecipitation of solid material. Such solids can then be removed bypressing or other separation procedures. However, not all of thehigh-melting solid material is removed from the oils by this processing,and the oils still tend to cloud when stored for extended periods oftime at low temperature. Moreover, the usual Winterizing treatmentundesirably tends to remove by entrainment a substantial portion of theolein fraction of the oil.

It has now been found that by means of the present invention the timefor storage at low temperatures without clouding can be greatly extendedfor salad oils.

Accordingly, it is an object of this invention to provide an improvedsalad oil which will remain free from clouding or crystal formation forlonger periods of time than will oils which either have been merelytreated by conventional Winterizing techniques or have not beenwinterized.

Other objects and advantageous features will be apparent from thefollowing detailed description.

The testing procedure for oils as used hereinafter involves holding theoil at a temperature of about 30 F. until a cloud forms in the oil. Asused herein, the term chill tes is intended to define the length oftime, after cooling the oil to 30 F. (unless some other temperature isspecified), until such a cloud forms.

In general, oils of this invention comprise a clear base salad oilcontaining dissolved therein a crystal inhibiting amount and at least0.001% by weight, of fatty ester of monosaccharidic material having anoxide ring structure and selected from the group consisting ofaldohexose, aldohexuronolactone, aldohexonolactone, methyl aldohexoside, and aldohexuronic acid. The aldohexose or aldohexosederivative should be at least 25% esterified, based on the totalhydroxyl availability. At least about ice 15% of the total fatty acid inthe ester is saturated fatty acid having from about 12 to about 24carbon atoms. The remainder of the fatty acid is selected from the groupconsisting of short chain fatty acids having from 2 to about 6 carbonatoms or unsaturated long chain fatty acids having from about 12 toabout 24 carbon atoms, the molar proportion of the said short chainfatty acids not substantially exceeding the total molar proportion ofthe said saturated and unsaturated long chain fatty acid.

It will be appreciated that the ester of aldohexose or of aldohexosederivative used in the practice of this invention usually will be areaction product containing a mixture of diiferent esters. For thisreason, the invention is defined in terms of average fatty acid contentper molecule.

By Way of example, a suitable aldohexosc ester for this invention isglucose esterified with an average of 1% palmitic acid groups. Otherlong-chain saturated fatty acid groups such as those of lauric,myristic, stearic, arachidic, behenic or lignoceric acids, and mixturesthereof, can be present in the ester in place of part or all of thepalmitic acid groups. The glucose ester must be at least 25% esterified,based on the total hydroxyl availability, and be esterified with atleast about 15%, based on the total fatty acid in the ester, oflong-chain saturated fatty acid. Subject to this limitation, the glucosecan be esterified additionially with short-chain fatty acids such asacetic, propionic, butyric, valeric, and caproic acids, or withlong-chain unsaturated fatty acids such as lauroleic, myristoleic,palmitoleic, oleic, linoleic, linolenic, elaidic, gadoleic, arachidonic,erucic, 'brassidic, clupanodonic and/or selacholeic acids.

Other suitable aldohexoses which can be used to form esters for use inthe practice of this invention are mannose and galactose. Examples ofsuitable aldohexose derivatives which can be similarly esterified foruse in this invention are glucuronolactone, glucuronic acid,galacturonic acid, gluconolactone, mannonolactone, and methyl glucoside.

A wide variety of oils can be used as base salad oils in the practice ofthis invention, either individually or as mixtures of oils. Includedamong suitable oils are the so-called natural salad oils such as oliveoil, sunflower seed oil, safilower oil, and sesame oil. Oils such ascottonseed oil and corn oil must be given a preliminary winterizing,de-waxing, or similar other treatment to remove the higher-meltingsolids to form a good base salad oil. Other oils, such as soybean oil,may require some hydrogenation to prevent rancidity with prolongedstorage, and the higher-melting glycerides formed during thishydrogenation treatment preferably are removed. Base salad oils can alsobe formed by directed, low-temperature interesterification of animal andvegetable fatty materials, followed by removal of higher-meltingglycerides formed during the reaction (US. Patent 2,442,532, issued June1, 1948, to E. W. Eckey). Another group of oils includes those in whichone or more short-chain fatty acids, such as acetic, replace thelonger-chain fatty acids present in natural triglyceride oils. Otherbase salad oils will suggest themselves to those skilled in the art,provided they have a suitable chill test as hereinbefore defined. Asused herein the term base salad oil is intended to include any salad oilwhich will not form solids immediately when cooled to 30 F.

The esters of aldohexose and aldohexose derivatives suitable for use inthis invention can be prepared by a variety of known methods. Forexample, the aldohexose or derivatives can be reacted with mixtures ofacid chlorides, or acid anhydrides, of suitable fatty acids. Aldohexoseor derivatives can also be catalytically esterified with mixtures ofmethyl esters of suitable fatty acids. It

is to be understood, however, that the invention is not to be limited toany specific method of preparation of the ester of aldohexose orderivative.

The ester and the base salad oil can be mixed together in any convenientmanner. For example, ester in liquid form can be mixed with the oil. Ifthe ester is in solid form, it can be dissolved in the coil, although itmay be desirable to heat the oil or the mixture of oil and ester tofacilitate solution. It is to be kept in mind, however, that in allcases the resulting product is merely a physical mixture and there is nochemical reaction between the ester and the oil.

The following examples will serve to further illustrate the invention.

Example 1 39.7 g. of glucose were partially esterified by reaction with60.5 g. of palmitoyl chloride in the presence of 1750 ml. pyridine. Theglucose was first dissolved in the warm pyridine and then the fatty acidchloride was slowly added thereto. The reaction mixture was allowed tostand at room temperature for about 20 hours. The solvent was thenpartially stripped off under high vacuum until about 250 ml. of thereaction mixture remained. The reaction mixture solution became cloudyand was then held in an ice bath and stirred until a white precipitateof about 80 g. of glucose partial palmitate was obtained. The partialester had a hydroxyl value of 286 and an average of about 1.8 esterifiedhydroxyl groups per molecule (36% esterified).

When 0.01% by weight of the said glucose ester was dissolved inwinterized cottonseed oil, the chill test was lengthened from 8 hours toabout 24 hours.

The average degree of esterificati-on of glucose can be controlled byvarying the ratio of reactants in the procedure of this example; andwhen a higher glucose ester such as glucose tetrapalmitate issubstituted for the glucose partial ester used in this example,substantially similar improvement in the chill test is obtained.

Example 2 Ten g. of glucose were partially esterified by reaction with25 g. of the fatty acid chlorides of cottonseed oil (about /2 linoleoyland about each of oleoyl and palmitoyl chlorides; these figures do notaccount for the presence of small amounts of several other acylchlorides, such as stearoyl chloride, which are also known to bepresent) in the presence of 500 ml. pyridine. The glucose was dissolvedin the warm pyridine and then the fatty acid chlorides were addedslowly. This reaction mixture was allowed to stand at room temperaturefor about 20 hours. The pyridine was then stripped off under high vacuumwith gentle heating. The resulting glucose partial ester had a hydroxylvalue of 163, a saponification value of 274, and an average of about 2.7esterified hydroxyl groups per molecule (54% esterified).

0.05% by weight of the glucose ester dissolved in winterized cottonseedoil lengthened the chill test from 8 hours to about 49 hours.

When equimolar portions of mannose and galactose are substituted forglucose in this example, substantially similar improvement in chill testresults are obtained.

Example 3 33 g. of methyl glucoside were partially esterified byreaction with 70 g. of palmitoyl chloride in the presence of 1000 ml.pyridine. The methyl glucoside was first dissolved in the pyridine andthen the fatty acid chloride was added slowly. The solvent was removedunder a high vacuum at an elevated temperature. After several waterwashings, 62 g. of the methyl glucoside partial palmitate product had ahydroxyl value of 149, an acid value of 22, and an average between 1 and2 esterified hydroxyl groups per molecule.

0.01% by Weight of the methyl glucoside ester dissolved in winterizedcottonseed oil lengthened the chill test from 8 hours .to about 24hours.

Other long chain fatty acid esters of glucose, methyl glucoside,glucuronolactone, glucuronic acid, and gluconolact-one and thecorresponding esters of the stereoisomeric aldohexoses and aldohexosederivatives which show excellent crystal inhibiting activity can beprepared by various methods including the methods described in Examples1-3 above, and may be similarly admixed with base oil to providecomparable improvement when subjected to the chill test. The followingexamples will serve to illustrate the crystal inhibiting activity withseveral of these esters.

Example 4 Solution in winterized cottonseed oil of 0.005% by weight ofglucono-delta-lactone ester having an average between one and twopalmitoyl groups per molecule lengthened the chill test from 8 to about24 hours. Similar results were obtained with 0.1% of the same ester insaid oil.

Example 5 Solution of 0.1% by weight of methylglucoside distearate inwinterized cottonseed oil lengthened the chill test from 8 hours togreater than 16 hours.

Example 6 Solution of 0.01% by weight of glucuronolacetone monopalmitatein winterized cottonseed oil lengthened the chill test from 8 hours toabout 40 hours.

When galacturonic acid is substituted for glucuronolactone in thisexample, substantially similar improvement in chill test results isobtained.

Example 7 Solution in winterized cottonseed oil of 0.1% by weight ofglucono-delta-lacetone ester having an average between three and fourpalmitoyl groups per molecule lengthened the chill test from 8 to about41 hours.

Example 8 Solution in refined, bleached soybean oil of 0.01% by weightof glucono-delta-lactone ester having an average between three and fourpalmitoyl groups per molecule lengthened the chill test from 5 /2 hoursto about 30 hours. When the concentration of the ester used in anotherportion of the oil was increased to about 0.1%, the chill test waslengthened from about 5 /2 hours to about 23% hours.

The following example illustrates one of the combined long and shortchain fatty esters of glucose herein described which show the excellentcrystal inhibiting activity of this invention.

Example 9 Solution of 0.1% by weight of diacetyl tripalmitoyl glucose ina sample of winterized cottonseed oil lengthened the chill test from 8hours to about 60 hours.

When winterized corn oil is substituted for winterized cottonseed oil inthis example, substantially similar improvement in the chill test isobtained.

Although it is desired not to be bound by any theory, it is believedthat inhibition of the formation of crystalline material in oil isaccomplished by selecting a material which, at the temperature at whichprotection is desired, will be substantially dissolved in the oil, butthe amount of inhibitor added preferably should be at a level not farbelow that at which precipitation of the inhibiting material in the oilwill occur. It is believed that the inhibitor acts by being adsorbed onthe invisible crystal nuclei of the higher-melting components of thesubstrate oil, so that further crystallization of these components is:greatly retarded. Materials having strong tendencies to be adsorbed canbe added at lower levels than materials: with weaker adsorptivetendencies.

A proper balance is required for the: optimum inhibiparticularlypromoted by unsaturated! (gor low mole weight) chain on the ester andadsorptive tendency as promoted by saturated chains. It would bepresumed that since trans-unsaturated chains are intermediate betweencis-unsaturated and saturated chains in their usual effect on solubilityor melting level, they would generally tend to be intermediate in theireffect on inhibition action. Under certain conditions, however, thecisand trans-chains may be comparable in their efiect on inhibitionpower.

If too large an amount of inhibitor is present, it will precipitate outof solution and possibly even promote crystallization of high-meltingsolids in the oil. Too small an amount of inhibitor, of course, will berelatively ineffective. Amounts of ester in excess of about 0.5%, byweight, are unnecessary as affording no significant added improvement ofthe oil.

What is claimed is:

1. A clear glyceride salad oil having superior resistance to depositionof high-melting solids and comprising a base salad oil having dissolvedtherein a crystal inhibiting amount and at least about 0.001%, byweight, of fatty acid ester of monosaccharidic material having an oxidering structure and selected from the group consisting of aldohexose,aldohexuronolactone, aldohexuronic acid, aldohexonolactone, and methylaldohexoside, the said material being at least 25% esterified, based onthe total hydroxyl availability, with at least about 15%, based on thetotal fatty acid in the ester, of saturated long chain fatty acid havingfrom about 12 to about 24 carbon atoms, the balance of the fatty acidbeing selected from the group consisting of short chain fatty acidshaving from 2 to about 6 carbon atoms and unsaturated long chain fattyacids having from about 12 to about 24 carbon atoms, the molarproportion of the said short chain fatty acids not substantiallyexceeding the total molar proportion of the said saturated andunsaturated long chain fatty acids.

2. A salad oil according to claim 1 wherein the monosaccharidic moietyof the ester is derived from glucose.

3. A salad oil according to claim 1 wherein the fatty acid groupsconsist essentially of palmitic acid groups.

4. A salad oil according to claim 1 wherein the fatty acid groupsconsist essentially of stearic acid groups.

5. A salad oil according to claim 1 wherein the fatty acid groupsconsist essentially of acetic and palmitic acid groups.

6. A salad oil according to claim 1 wherein the fatty acid groupscomprise linoleic, oleic, and palmitic acid groups.

7. A clear glyceride salad oil having superior resistance to depositionof high-melting solids and comprising winterized cottonseed oil havingdissolved therein about 0.1%, by weight, of methylglucoside distearate.

8. A clear glyceride salad oil having superior resistance to depositionof high-melting solids and comprising winterized cottonseed oil havingdissolved therein about 0.1%, by weight, of glucono-delta-lactone esterhaving an average of between three and four palmitoyl groups permolecule.

9. A clear glyceride salad oil having superior resistance to depositionof high-melting solids and comprising winterized cottonseed oil havingdissolved therein about 0.1%, by weight, of diacetyl tripalmitoylglucose.

References Cited by the Examiner UNITED STATES PATENTS 2,223,558 12/40Epstein 99-123 2,266,591 12/41 Eckey et al 99163 A. LOUIS MONACELL,Primary Examiner.

1. A CLEAR GLYCERIDE SALAD OIL HAVING SUPERIOR RESISTANCE TO DEPOSITIONOF HIGH-MELTING SOLIDS AND COMPRISING A BASE SALAD OIL HAVING DISSOLVEDTHEREIN A CRYSTAL INHIBITING AMOUNT AND AT LEAST AOBUT 0.0041%, BYWIEGHT, OF FATTY ACID ESTER OFMONOSACCHARIDIC MATERIAL HAVING AN OXIDERING STRUCTURE AND SELECTED FROM THE GROUP CONSISTING OF ALDOHEXOSE,ALDOHEXURONOLACTONE, ALDOHEXURONIC ACID, ALDOHEXONOLACTONE, METHYLALDOHEXOSIDE, THE SAID MATERIAL BEING AT LEAST 25% ESTERIFIED, BASED ONTHE TOTAL HYDROXYL AVAILABILITY, WITH AT LEAST ABOUT 15%, BASED ON THETOTAL FATTY ACID IN THE ESTER, OF SATURATED LONG CHAIN FATTY ACID HAVINGFROM ABOUT 12 TO ABOUT 24 CARBON ATOMS, THE BALANCE OF THE FATTY ACIDBEING SELECTED FROM THE GROUP CONSISTING OF SHORT CHAIN FATTY ACIDSHAVING FROM 2 TO ABOUT 6 CARBON ATOMS AND UNSATURATED LONG CHAIN FATTYACIDS HAVING FROMABOUT 12 TOABOUT 2'' CARBON ATOMS, THE MOLAR PROPORTIONOF THE SAID SHORT CHAIN FATTY ACIDS NOT SUBSTANTIALLY EXCEEDING THETOTAL MOLAR PROPORTION OF THE SAID SATURATED AND UNSATURATD LONG CHAINFATTY ACIDS.